Mold system including separable, variable mold portions for forming casting article for investment casting

ABSTRACT

A mold system and method for forming a casting article for investment casting is disclosed. The mold system includes a mold for receiving therein a selected core chosen from a plurality of varied cores. The mold includes a plurality of separable mold portions that are coupleable together to create the mold and configured to form a sacrificial material from a sacrificial material fluid about the selected core. At least one selected separable mold portion of the plurality of separable mold portions includes a set of varied interchangeable versions of the at least one selected separable mold portion. Each varied interchangeable version of the selected separable mold portion is configured to accommodate a different core of the plurality of varied cores. A number of systems for controlling a temperature of the mold are also disclosed.

BACKGROUND OF THE INVENTION

The disclosure relates generally to inserts for investment casting, andmore particularly, to a mold system for forming a casting article forinvestment casting.

Investment casting is used to manufacture a large variety of industrialparts such as turbomachine blades. Investment casting uses a castingarticle having a sacrificial material pattern to form a ceramic mold forthe investment casting. Certain types of casting articles may include acore or insert within the sacrificial material pattern. The core definesan interior structure of the component and becomes a part of the ceramicmold used during the investment casting. The core can include a largevariety of intricate features that define an interior structure of thecomponent. Cores can be additively manufactured to allow for rapidprototyping and manufacturing of the cores. The casting article is madeby molding a sacrificial material fluid, such as hot wax or a polymer,about the core in a mold that defines the shape of the componentsurrounding the core. The hardened sacrificial material formed about thecore defines the shape of the component for the investment casting.

Each casting article, either individually or in a collection thereof,can be dipped in a slurry and coated with a ceramic to form a ceramicmold for the investment casting. Once the sacrificial material isremoved from the ceramic mold, the mold can be used to investment castthe component using a molten metal, e.g., after pre-heating the ceramicmold. Once the molten metal has hardened, the ceramic mold can beremoved, and the core can be removed using a leachant. The component canthen be finished in a conventional fashion, e.g., heat treating andconventional finishing.

Investment casting is a time consuming and expensive process, especiallywhere the component must be manufactured to precise dimensions. Inparticular, where precise dimensions are required, formation of thecasting article must be very precise. Each mold used to form the castingarticle can be very costly, and can take an extensive amount of time tomanufacture. Consequently, any changes in the core or the component canbe very expensive and very time consuming to address. Other challengesthat can be costly and time consuming to address are unforeseenweaknesses in the core that cause it to crack or break either duringformation of the casting article (e.g., during casting of thesacrificial material about the core), or during the actual investmentcasting. For example, high pressure sacrificial fluid injected into amold about the core during casting article formation can crack or breakthe core, or molten metal injected during the investment casting cancrack or break the core. In the former case, the core must be adjusted,and in the latter case, the core and/or the casting article mold mayneed adjusting. In any event, the changes are costly and time consuming.Currently, there is no mechanism to proactively address the corecracking/breaking challenges.

One approach to reduce time and costs employs additive manufacture ofthe cores and molds for making the casting article. In particular,additive manufacture allows for more rapid turnaround for design changesin cores and/or the component leading up to the component manufacturingsteps. Additive manufacturing (AM) includes a wide variety of processesof producing an object through the successive layering of materialrather than the removal of material. Additive manufacturing can createcomplex geometries without the use of any sort of tools, molds orfixtures, and with little or no waste material. Instead of machiningobjects from solid billets of material, much of which is cut away anddiscarded, the only material used in additive manufacturing is what isrequired to shape the object. Current categories of additivemanufacturing may include: binder jetting, material extrusion, powderbed infusion, directed energy deposition, sheet lamination and vatphotopolymerization.

Additive manufacturing techniques typically include taking athree-dimensional (3D) computer aided design (CAD) file of the object(e.g., core and/or casting article mold) to be formed, electronicallyslicing the object into layers (e.g., 18-102 micrometers thick) tocreate a file with a two-dimensional image of each layer (includingvectors, images or coordinates) that can be used to manufacture theobject. The 3D CAD file can be created in any known fashion, e.g.,computer aided design (CAD) system, a 3D scanner, or digital photographyand photogrammetry software. The 3D CAD file may undergo any necessaryrepair to address errors (e.g., holes, etc.) therein, and may have anyCAD format such as a Standard Tessellation Language (STL) file. The 3DCAD file may then be processed by a preparation software system(sometimes referred to as a “slicer”) that interprets the 3D CAD fileand electronically slices it such that the object can be built bydifferent types of additive manufacturing systems. The object code filecan be any format capable of being used by the desired AM system. Forexample, the object code file may be an STL file or an additivemanufacturing file (AMF), the latter of which is an internationalstandard that is an extensible markup-language (XML) based formatdesigned to allow any CAD software to describe the shape and compositionof any three-dimensional object to be fabricated on any AM printer.Depending on the type of additive manufacturing used, material layersare selectively dispensed, sintered, formed, deposited, etc., to createthe object per the object code file.

One form of powder bed infusion (referred to herein as metal powderadditive manufacturing) may include direct metal laser melting (DMLM)(also referred to as selective laser melting (SLM)). This process isadvantageous for forming metal molds for forming casting articles. Inmetal powder additive manufacturing, metal powder layers aresequentially melted together to form the object. More specifically, finemetal powder layers are sequentially melted after being uniformlydistributed using an applicator on a metal powder bed. Each applicatorincludes an applicator element in the form of a lip, brush, blade orroller made of metal, plastic, ceramic, carbon fibers or rubber thatspreads the metal powder evenly over the build platform. The metalpowder bed can be moved in a vertical axis. The process takes place in aprocessing chamber having a precisely controlled atmosphere. Once eachlayer is created, each two dimensional slice of the object geometry canbe fused by selectively melting the metal powder. The melting may beperformed by a high powered irradiation beam, such as a 100 Wattytterbium laser, to fully weld (melt) the metal powder to form a solidmetal. The irradiation beam moves or is deflected in the X-Y direction,and has an intensity sufficient to fully weld (melt) the metal powder toform a solid metal. The metal powder bed may be lowered for eachsubsequent two dimensional layer, and the process repeats until theobject is completely formed. In order to create certain larger objectsfaster, some metal additive manufacturing systems employ a pair of highpowered lasers that work together to form an object, like a mold. Otheradditive manufacturing processes, such as 3D printing, may form layersby dispensing material in layers.

Although additive manufacturing of cores and/or molds for castingarticle formation has reduced time and cost for adjusting cores and/ormolds, challenges remain. Most notably, current mold systems andpractices for forming a casting article form one mold regardless ofvariations in cores. When variations in cores are subtle or when thecore has fine or intricate features, it can result in cracked or brokencores and/or imprecise casting articles. Where variations in cores aremore profound, e.g., where they share a common structure but also haveother structure that varies widely to build different components, eachvariation of core must have its own mold. Current mold systems used forforming the casting articles are also not sufficiently thermallyadjustable to accommodate sacrificial material fluid flow acrossdifferent cores.

Another challenge with current investment casting is ensuring coreswithin a casting article can withstand the actual investment casting,i.e., the casting of a molten metal about the core. The current practiceincludes a trial and error approach in which a casting article is usedto perform an investment casting to determine its efficacy. Duringinvestment casting, the core may, for example, break, crack or preventadequate molten metal flow to form the component. In the absence of anymechanism to predict core efficacy, when a problem is identified duringinvestment casting, changes to the core, the metal casting article mold,and/or the casting article formation process must be made, all of whichare time consuming and expensive.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the disclosure provides a mold system for forming acasting article for investment casting, the mold system comprising: amold for receiving therein a selected core chosen from a plurality ofvaried cores, the mold including a plurality of separable mold portionsthat are coupleable together to create the mold and configured to form asacrificial material from a sacrificial material fluid about theselected core, wherein at least one selected separable mold portion ofthe plurality of separable mold portions includes a set of variedinterchangeable versions of the at least one selected separable moldportion, each varied interchangeable version of the selected separablemold portion configured to accommodate a different core of the pluralityof varied cores.

A second aspect of the disclosure provides a method of forming a castingarticle for investment casting, the casting article including asacrificial material about a core, the method comprising: having aplurality of separable mold portions for a mold for forming the castingarticle additively manufactured, the plurality of mold portionsincluding a set of varied interchangeable versions of a selectedseparable mold portion, each varied interchangeable version of theselected separable mold portion configured to accommodate a differentcore of a plurality of varied cores; forming the mold about a selectedcore of the plurality of varied cores by coupling two or moremold-selected separable mold portions together, the mold-selectedseparable mold portions selected to accommodate the selected core of theplurality of varied cores; and casting the casting article byintroducing a sacrificial material fluid into the mold and about theselected core.

A third aspect may include a mold system for forming a casting articlefor investment casting, the mold system comprising: a mold for receivingtherein a core, the mold including a plurality of sacrificial materialfluid input zones configured to receive a sacrificial material fluid toform a sacrificial material about the core; and a sacrificial materialheating system configured to heat a plurality of flows of thesacrificial material fluid to different temperatures, wherein onesacrificial material fluid input zone receives one of the plurality offlows of the sacrificial material fluid at a first temperature andanother sacrificial material fluid input zone receives another of theplurality of flows of the sacrificial material fluid at a second,different temperature.

A fourth aspect includes a mold system for forming a casting article forinvestment casting, the mold system comprising: a mold for receivingtherein a core, the mold including a plurality of separable moldportions that are coupleable together to create the mold and configuredto form a sacrificial material from a sacrificial material fluid aboutthe core, wherein each separable mold portion includes a mold thermalconducting conduit therein configured to pass a temperature controlledthermal fluid therethrough to control a temperature of at least thesacrificial material fluid within the respective separable mold portion;and a thermal fluid controller controlling a temperature of thetemperature controlled thermal fluid passing through each of theplurality of separable mold portions, at least one separable moldportion having the temperature controlled thermal fluid passingtherethrough having a temperature different than another separable moldportion.

A fifth aspect includes a method of forming a casting article forinvestment casting, the casting article including a sacrificial materialabout a core, the method comprising: controlling a temperature of aplurality of sacrificial material fluid input zones in a mold configuredto receive a sacrificial material fluid to form a sacrificial materialabout the core that is positioned within the mold; and forming thecasting article by introducing a sacrificial material fluid into themold and about the selected core.

The illustrative aspects of the present disclosure are designed to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 shows a perspective front view of a mold system according toembodiments of the disclosure.

FIG. 2 shows a perspective rear view of a mold system according toembodiments of the disclosure.

FIG. 3 shows a front, see-through perspective view of the mold systemaccording to embodiments of the disclosure.

FIG. 4 shows a side, see-through perspective view of the mold systemaccording to embodiments of the disclosure.

FIGS. 5-7 show schematic side views of illustrative varied cores.

FIG. 8 show a schematic top view of illustrative overlaid varied cores.

FIG. 9 shows a cross-sectional top view of a first core in a mold systemincluding separable mold portions according to embodiments of thedisclosure.

FIG. 10 shows a cross-sectional top view of a second, different corefrom that of FIG. 9 in a mold system including different separable moldportions according to embodiments of the disclosure.

FIG. 11-14 show varied views of a pair of separable mold portions of amold system according to embodiments of the disclosure.

FIGS. 15-18 show varied views of another pair of separable mold portionsof a mold system according to embodiments of the disclosure.

FIG. 19 shows a perspective view of an illustrative core positioneraccording to one embodiment of the disclosure.

FIG. 20 shows a schematic, cross-sectional view of an illustrative moldsystem including a mold thermal fluid controller for deliveringtemperature controlled thermal fluid to mold thermal conducting conduitsin the mold, and showing varied mold thermal conducting conduit pathsand positions according to various embodiments of the disclosure.

FIG. 21 shows a schematic, cross-sectional view of an illustrative moldsystem including a sacrificial material heating system according tovarious embodiments of the disclosure.

FIG. 22 shows a flow diagram illustrating methods according to variousembodiments of the disclosure.

It is noted that the drawings of the disclosure are not to scale. Thedrawings are intended to depict only typical aspects of the disclosure,and therefore should not be considered as limiting the scope of thedisclosure. In the drawings, like numbering represents like elementsbetween the drawings.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the disclosure provides a mold system including amold for receiving therein a selected core chosen from a plurality ofvaried cores. The mold is configured to form a sacrificial material froma sacrificial material fluid, e.g., wax or a polymer, about a selectedcore to create a casting article. The casting article including the coreand hardened sacrificial fluid material thereabout are used in aconventional manner to form a ceramic mold used for subsequentinvestment casting of a component. The varied cores may differ in anynumber of ways such as shape, dimensions, contours, material properties,etc. In one example, each varied core can be close in shape, but havesome dimensional variance. In another example, part of a casting articlemold may be employed to form a number of components that share a common,first internal structure formed by a common core, but include a numberof different, second internal structures formed by a second, differentcore. That is, the common, first internal structure may be formed by afirst, common core, while the different, second internal structures maybe made by various second cores. The cores may be made from ceramic orother refractory material (e.g., niobium, molybdenum, tantalum, tungstenor rhenium), metal, metal alloy or combinations thereof.

In order to address the challenge of varied cores, a mold according toembodiments of the disclosure includes a plurality of separable moldportions that are coupleable together to create the mold. In contrast toconventional mold systems, at least one selected separable mold portionof the plurality of separable mold portions includes a set of variedinterchangeable versions of the at least one selected separable moldportion. Each varied interchangeable version of the selected separablemold portion is configured to accommodate a different core of theplurality of varied cores. In this fashion, variations in cores, whethersimple dimensional differences or widely different internal structuresto create different components, can be readily accommodated withoutforming a complete, expensive metal mold for each core variation.Embodiments of the disclosure also leverage the separable mold portionsto provide precise temperature control across the mold to address anumber of issues such as certain core areas being prone to cracking orbreaking.

Referring to FIGS. 1 and 2 , a front perspective view and a rearperspective view, respectively, of a mold system 100 according toembodiments of the disclosure are illustrated. Further, FIG. 3 shows afront, see-through perspective view, and FIG. 4 shows a side,see-through perspective view of mold system 100 from FIGS. 1-2 . It isappreciated that according to embodiments of the disclosure, mold system100 is used for forming a casting article 102 (FIGS. 3-4 ) forinvestment casting. For purposes of description, as shown in FIGS. 3-4 ,the disclosure shows the component to be built as a turbomachine airfoil104. It will be readily understood that the teachings of the disclosureare applicable to any component capable of investment casting and whichis to include an internal structure formed by a core.

Mold system 100 includes a mold 110 for receiving therein a selectedcore chosen from a plurality of varied cores. The variation in cores cantake any of a large number of forms. In the example shown in FIGS. 3 and4 , two different cores 112A, 112B (collectively “cores 112”) areillustrated that collectively form an internal structure in theturbomachine airfoil, e.g., cooling channels, support structure, etc. Inthe turbomachine airfoil example, a core 112A may form a portionincluding a leading edge of the airfoil, while core 112B forms a portionincluding a trailing edge of the airfoil. In one non-limiting example, anumber of different turbomachine airfoils can be formed by using asingle leading edge core 112A, and a variety of different, trailing edgecores 112B. FIGS. 5-7 show schematic side views of a number of examplesin which single leading edge core 112A is used, and a variety ofdifferently shaped cores 112B are employed. It is recognized that theportion of the component that changes can also differ from component tocomponent, e.g., for an airfoil, the leading edge or a root portion 118may also vary.

FIG. 8 , in contrast to FIGS. 5-7 , shows a top view of varied cores112A, 112B in which the difference is simply a dimensional or shapevariation created by variation during core manufacture, e.g., viaadditive manufacturing. In this setting, variations from core to corecan be identified in any now known or later developed fashion such asbut not limited to: blue light scans or point cloud scans. Thedifferences identified can be used to generate a model of the actualcores 112A, 112B, which can then be used to adjust mold 110 accordingly,e.g., to maintain a desired spacing between and interior surface 132 ofmold 110 and core 112 to ensure proper positioning and thickness ofsacrificial material 130. Modifications to mold 110 can be made duringmanufacturing of the mold (e.g., using additive manufacturing and/orcomputer aided design software systems), and in particular, separablemold portions 120 that form the mold. Core 112 can be formed in any nowknown or later developed fashion. In one embodiment, core 112 is formedby additive manufacturing, e.g., 3D printing.

Mold 110 includes a plurality of separable mold portions 120A-D(collectively “separable mold portions 120”) that are coupleabletogether to create the mold. As shown in FIGS. 1-4 , four mold portions120A-D are provided in the example shown. It is understood however thatany number of separable mold portions 120 may be employed, e.g., two ormore. As understood, mold 110 is configured to form sacrificial material130 from a sacrificial material fluid (i.e., sacrificial material in afluid form) about a selected core 112. Core 112 is positioned withinmold 110 and is spaced from interior surface 132 of mold 110 such thatsacrificial material fluid can readily flow between core 112 and theinterior surface of the mold to create casting article 102. Thesacrificial material can be any now known or later developed materialthat is capable of injecting in a fluid form, and that is sufficientlyrigid in a solid state to hold its shape during investment castingceramic mold formation. Sacrificial material may include but is notlimited to: wax or polymer.

As shown in FIGS. 9 and 10 , any selected separable mold portion 120 ofplurality of separable mold portions 120A-D in a particular mold caninclude a set of varied interchangeable versions thereof. In the exampleshown, a set of separable mold portions 120E (FIG. 9 ) and 120F (FIG. 10) are provided for a portion including a trailing edge of a turbomachineairfoil 104. While two varied interchangeable versions are shown, anynumber may be employed to accommodate any number of varied cores 112,e.g., sets with many similar mold portions can be made. Each variedinterchangeable version 120E, 120F of the selected separable moldportion 120 may be configured to accommodate a different core 112 of theplurality of varied cores 112. In the example shown in FIG. 9 , aseparable mold portion 120E is shaped to accommodate core 112B, while asshown in FIG. 10 , separable mold portion 120F is shaped to accommodatedifferent core 112A in the same position of mold 110. Each variedinterchangeable version of a selected separable mold portion 120 can bedifferent in a number of ways such as but not limited to: mold openingshape, size: length, width, height; thermal cooling circuit (presence orpath, described elsewhere herein); coefficient of thermal expansion;coefficient of heat transfer; material and/or material properties suchas yield strength, grain boundary structure, surface finish, etc. In anyevent, selected separable mold portions 120E, 120F are configured to bepositioned in the same position within mold 110 to complete the mold,but have different interior surfaces 132 to accommodate varied cores112A, 112B. As will be described herein, separable mold portions 120E,120F may include a number of other features that allow for, among otherthings, proper coupling and thermal control.

Each separable mold portion 120 may include a metal alloy, an acrylicbased material such as but not limited to poly-methyl methylacrylate(PMMA), or a material having glass transition temperature above 70° C.(approximately 160° F.). Where a metal alloy is employed, separable moldportions 120 can be readily manufactured with the afore-mentionedcustomized structure using, for example, additive manufacturing. Moreparticularly, a metal powder additive manufacturing process may be usedto form metal separable mold portions 120. Metal powder additivemanufacturing may include, for example, direct metal laser melting(DMLM). It is understood that the general teachings of the disclosureare equally applicable to other forms of metal powder additivemanufacturing such as but not limited to direct metal laser sintering(DMLS), selective laser sintering (SLS), electron beam melting (EBM),and perhaps other forms of additive manufacturing. Where separable moldportions 120 include an acrylic-based material or material with glasstransition temperature above 70° C., mold portions 120 can bemanufactured by, for example, stereolithography or 3D printing (e.g.,using stereolithography resins). Other processes may also be employed tomanufacture separable mold portions 120, e.g., casting and machining.

FIGS. 11-14 show various views of selected separable mold portions 120C,120D from a top portion of mold 110 in FIGS. 1-4 , and FIGS. 15-18 showvarious views of selected separable mold portions 120A, 120B from abottom portion of mold 110 in FIGS. 1-4 . More particularly, FIGS. 11and 12 show perspective views of mating separable mold portions 120C,120D; FIG. 13 shows a bottom view of both mold portions 120C, 120D; FIG.14 shows a perspective view of both mold portions 120C, 120D; FIGS. 15and 16 show perspective views of mating separable mold portions 120A,120B; FIG. 17 shows a side view of both mold portions 120A, 120B; andFIG. 18 shows a perspective view of both mold portions 120A, 120B. Asillustrated, each separable mold portion 120 may include any structurenecessary for sealingly coupling with other mold portions. For example,mold portions 120A-D may include mating surfaces 136 configured to seatand mate with an adjacent mold portion. Surfaces 136 can be any shapenecessary to allow mating, e.g., planar and/or curved. Surfaces 136 aredimensioned so as to prevent sacrificial material 130 fluid from passingtherethrough when mated. Further, certain mold portion(s) 120A-D mayinclude gasket grooves 138 (FIGS. 13, 15-18 ) configured to receive agasket (not shown) therein for sealing with an adjacent mold portion.Further, certain mold portion(s) 120C-D may include ceramic core top-botfixturing ends 140. Separable mold portions 120A, 120B, 120C, 120D arealso designed to be mixed and matched, for example separable moldportions 120A and 120B forming a bottom portion of mold 110 may becommon across multiple airfoil designs having differing separable moldportions 120C, 120D that form top portion of mold 110.

Certain mold portion(s) 120A-D may also include a core positionerreceiver 144 therein. Each core positioner receiver 144 is configured toreceive a core positioner 146 (FIGS. 2 and 19 ) therein that extendsthrough a respective mold portion 120 to contact and appropriatelyposition a respective core 112 relative to interior surface 132 of mold110. That is, position core 112 spaced from an interior surface 132 ofmold 110 to define the position and thickness of sacrificial material130 about the core. Core positioner receivers 144 are thus anotherfeature of each separable mold portion 120 that can be varied toaccommodate varied cores 112. Each core positioner receiver 144 mayinclude a hole extending from interior surface 132 of mold 110 to anexterior surface 145 of mold 110, and may include a counter-bore on theexternal surface of mold 110. Mold system 100 may include a plurality ofcore positioners 146 (FIG. 2 ) configured to position the selected core112 via core positioner receivers 144 in the at least one of theplurality of separable mold portions 120. In one embodiment, each corepositioner 146 (FIG. 2 ) may have a selected length to position arespective portion of a selected core 112 relative to interior surface132 of mold 110. In this case, a set of core positioners 146 (FIG. 2 )may be provided for each mold portion 120 and/or for each varied core112. In another embodiment, core positioner 146 (FIG. 19 ) may beadjustable in each core positioner receiver 144 so as to accommodate avariety of mold portions 120 and/or a number of varied cores 112. Forexample, as shown in FIG. 19 , a core positioner 146 may include a head148 coupled to a rod 150. Head 148 may be threaded so as to mate andadjustably seat in a counter-threaded core positioner receiver 144 in aseparable mold portion 120. As head 148 is threadably inserted, thepositon of rod 150 relative to interior surface 132 changes toaccommodate contact with rod 150 with an external surface of differentcores 112. Head 148 may include any structure necessary to allow for theadjustment, e.g., a screwdriver head. In this fashion, each adjustablecore positioner 146 (FIG. 19 ) may be configured to position a number ofthe plurality of varied cores 112 in mold 110.

Returning to FIGS. 11-18 , certain separable mold portions, e.g., 120Ain FIG. 15 , may include air flow path(s) 152 to allow air to exit mold110. Air flow path(s) 152 may be provided wherever necessary to ensureair removal during operation.

Referring to FIGS. 1, 2 and 14-18 , plurality of separable mold portions120A-D may be fastened together in a number of ways. As shown in FIGS. 1and 2 , fasteners 160 may be used to selectively couple plurality ofseparable mold portions together, e.g., 120B to 120D and 120A to 120C.Fasteners 160 can take any form to hold mold portions 120A-D togetherduring operation, e.g., external clamps held in position by bolts, seatsin mold portions (shown), screws, etc. Certain separable mold portions120A-D may also include mating fastener holes 162 for receiving afastener (not shown) therein, e.g., threaded bolt, screw, etc., toselectively fasten mold portions together. For example, as shown inFIGS. 11 and 12 , separable mold portions 120C and 120D may includemating fastener holes 162, and as shown in FIGS. 15 and 16 , separablemold portions 120A and 120B may include mating fastener holes 162.Mating fastener holes 162 (in one or both separable mold portions beingfastened) may include a mechanism to secure the fastener, e.g., matingthreads, locking seat, etc. In addition to individual fastening ofseparable mold portions 120A-D, any now known or later developed moldlocking press may be employed to further hold mold 110 together duringuse.

Mold system 100 also provides mechanisms for controlling a temperatureof mold 110. In particular, separable mold portions 120 provide for moreprecise thermal control than conventional systems. Temperature controlof mold 110, and in particular each separable mold portion 120 or a zoneincluding a certain separable mold portion 120 may be desired for anumber of reasons. For example, temperature control allows one to:maintain a desired viscosity and/or temperature of sacrificial materialfluid, maintain a desired temperature of a core 112, protect mold 110from overheating damage, and preheat mold 110 to ensure proper casting.Further, certain sacrificial material fluids, e.g., wax or certainpolymers, may require a certain temperature to create a fluid formand/or maintain an appropriate temperature for creating casting article102. As will be described, the temperature control can be customized andcontrolled in a number of ways according to embodiments of thedisclosure.

In one embodiment, as shown for example in FIGS. 11, 12, 15 and 16 ,each separable mold portion 120A-D may also include a mold thermalconducting conduit 164 therein configured to conduct a temperaturecontrolled thermal fluid therethrough to control a temperature of atleast the respective separable mold portion 120. Mold thermal conductingconduits 164 may be deemed “closed loop” because they are arranged toprovide a complete path followed by temperature controlled thermal fluid176 as it is fed from mold thermal fluid controller 180 to inputport(s), through the respective portion of mold portion(s) 120A-D andthen to output port(s). Temperature controlled thermal fluid 176 usedcan be any now known or later developed heat conducting fluid, e.g.,air, water, antifreeze, etc., appropriate for the mold material.Temperature controlled thermal fluid 176 may add heat to a respectiveseparable mold portion 120A-D, and/or cool it. Temperature controlledthermal fluid 176 may be used to preheat mold 110 and/or maintain atemperature during casting article 102 formation. It is recognized thatwhile temperature controlled thermal fluid 176 passes through arespective separable mold portion 120A-D, it may transfer thermal energynot just to/from the particular mold portion through which it passes butalso to neighboring structure, the sacrificial material fluid and/orcore 112.

Each varied interchangeable version of the at least one selectedseparable mold portion 120A-D may include a mold thermal conductingconduit 164 different than the mold thermal conducting conduit in theother separable mold portions of the set. In this manner, each versionof a selected separable mold portion 120A-D can have its respectivethermal conducting path customized for the situation for which the moldportion is built. For example, as shown in FIG. 9 , a certain core 112Bmay require mold thermal conducting conduits 164 that pass in closeproximity to interior surface 132 to maintain the core and/orsacrificial material 130 fluid at a certain desired temperature, e.g.,less than 0.5 centimeters. In contrast, as shown in FIG. 10 , anothercore 112B may have mold thermal conducting conduits 164 that do not passas close to interior surface 132, e.g., greater than 0.5 centimeters.Again, each separable mold portion 120A-D and any mold thermalconducting conduits 164 therein can be customized for the expectedsituation for which it was built. The customization of mold thermalconducting conduits 164 can take any form including but not limited to:conduit number, cross-sectional area, length, shape, position/path,etc., and temperature controlled thermal fluid temperature, type, flowrate, etc.

FIG. 20 shows a schematic, cross-sectional view of a mold 110 includingvarious mold thermal conducting conduits 164A-E illustrating examplepaths and/or positions at which they can be employed. As shown in FIG.20 , mold thermal conducting conduit(s) 164A-E (collectively “moldthermal conducting conduits 164”) may take any path through a respectivemold portion including but not limited to: straight line 164A, curvedline 164B, loop(s) 164C, helical or spiral 164D, sinusoidal 164E, etc.As also shown in FIG. 20 , not all separable mold portions 120 needinclude a mold thermal conducting conduit, e.g., portion 120K is devoidof conduits. As also shown in FIG. 20 , external mold thermal conductingconduit(s) 168 may also be provided to route conduit paths on exteriorsurface 145 of, e.g., mold portion(s) 120M. Any now known or laterdeveloped ports 170 can be provided on exterior surface 145 of moldportion(s) 120 for fluidly coupling to external conduits 174 (oneexample shown in FIG. 20 ) that fluidly communicate with a mold thermalfluid controller 180 configured to control a temperature of each of theplurality of separable mold portions 120K-N or a zone including aportion of selected separable mold portions.

Mold thermal fluid controller 180 can include any now known or laterdeveloped temperature controlled thermal fluid temperature controlsystem for creating any number of temperature controlled thermal fluid176 flows, each at a specific temperature, e.g., a multi-tiered heatexchanger such as Thermolator TW Series water temperature control unit.Any necessary pumps to move temperature controlled temperaturecontrolled thermal fluid 176 may also be provided. Mold thermalconducting conduits 164 can be arranged to control the temperature of aparticular separable mold portion 120 and/or a sacrificial materialfluid input zone 190. With regard to the zones, one or more mold thermalconducting conduit(s) 164 may act to control a temperature of a definedsacrificial material fluid input zone 190A-C (3 shown). Each zone 190A-Cis configured to receive a sacrificial material fluid to form asacrificial material about the core at a particular temperature. Eachzone 190A-C can be defined by, for example, any desired area and/orvolume of mold 110, any area and/or volume of the void to be filled bysacrificial material 130 fluid, and/or any area and/or volume of core112. Each separable mold portion 120A-C may include at least onesacrificial material fluid input zone 190A-C, i.e., zones do notnecessarily match mold portions.

At least one separable mold portion 120 can have temperature controlledthermal fluid 176 passing therethrough having a temperature differentthan another separable mold portion 120. Similarly, each zone 190A-C canhave temperature controlled thermal fluid 176 passing through or near insuch a way as to have a temperature different than another zone. In anyevent, a mold thermal conducting conduit 164 may control a temperatureof at least the sacrificial material 130 fluid within at least onerespective separable mold portion 120, and perhaps other areas such asthose downstream of the mold portion in which the conduit exists. Eachzone 190A-C, for example, can have a temperature controlled therein tocontrol, for example, the viscosity and other flow characteristics ofsacrificial material 130 fluid in the respective zone to accommodate anycasting/injection issues specific to that zone including but not limitedto: difficult wetting/flow conditions, and/or core 112 issues. Forexample, the temperature of a zone 190A-C can be controlled based on acharacteristic of core 112, e.g., fragility, difficult wetting, etc., inthe respective zone. In this manner, core 112 damage and sacrificialmaterial fluid flow can be readily controlled, and quality castingarticle 102 formation can be attained. Further, certain mold 110materials may require using sacrificial material fluid having a certainmaximum temperature that does not damage the mold, e.g., a PMMA mold.Each zone 190A-C temperature can also be controlled to prevent molddamage by sacrificial material fluid overheating. The temperature ofeach mold portion 120 can be similarly controlled.

Turning to FIG. 21 , a schematic cross-sectional view of a mold system200 according to a further embodiment of the disclosure is illustrated.Mold system 200 may be substantially similar to mold system 100 asdescribed herein. For example, mold system 200 includes a mold 210 forreceiving therein core 112, and mold 210 includes plurality of separablemold portions 120A-D that are coupleable together to create the mold andconfigured to form the sacrificial material from the sacrificialmaterial fluid about the core. Further, a selected separable moldportion, e.g., 120E, F (FIGS. 9-10 ), of the plurality of separable moldportions 120 includes a set of varied interchangeable versions of the atleast one selected separable mold portion. Each varied interchangeableversion of the selected separable mold portion 120 may be configured toaccommodate a different core 112 of a plurality of varied cores. In theFIG. 21 embodiment, however, mold system 200 may have more than onesacrificial material fluid input 284 thereto for receiving more than onesacrificial material fluid flow 286A-C. For example, each separable moldportion 120 may have one or more sacrificial material fluid inputs 284.Also, some separable mold portions 120 may be devoid of sacrificialmaterial fluid inputs, e.g., portion 120A in the example of FIG. 21 .

In addition, mold system 200 may also include a sacrificial materialfluid heating system 202 to control the temperature and viscosity ofsacrificial material 130 fluid, and indirectly control the temperatureof mold portions 120. Sacrificial material heating system 202 canoperate alone or in addition to mold thermal fluid controller 180(latter shown in simpler fashion in FIG. 21 than in FIG. 20 forclarity). Sacrificial material fluid temperature control can be madebased on separable mold portions 120 and/or zones. Regarding zones, moldsystem 200 may include plurality of sacrificial material fluid inputzones 290A-C configured to receive a sacrificial material fluid 286A-Cflows to form a sacrificial material 130 about the core. One or moresacrificial material inputs 284A-C alone or in conjunction with moldthermal conducting conduits 164A-E (FIG. 20 ) may act to control atemperature of a sacrificial material fluid input zone 290A-C (3 shown)configured to receive a sacrificial material fluid to form a sacrificialmaterial about the core. As noted, each zone 290A-C can be defined by,for example, any desired area and/or volume of mold 210, any area and/orvolume of the void to be filled by sacrificial material fluid, and/orany area and/or volume of core 112. Each separable mold portion 120A-Dmay include at least one sacrificial material fluid input zone 290A-C.Each zone 290A-C can have a temperature of sacrificial material fluidinjected therein (and/or temperature controlled thermal fluid senttherethrough) controlled to control, for example, the viscosity andother flow characteristics of sacrificial material 130 fluid in therespective zone to accommodate any injection issues therein includingbut not limited to: difficult wetting/flow conditions, and/or core 112issues. The temperature of the sacrificial material fluid received ineach sacrificial material fluid input zone 290A-C may be based on, forexample, a characteristic of core 112, e.g., fragility, difficultwetting, etc., in the respective sacrificial material input zone.Sacrificial material 130 fluid flows 286A-C can also be controlled basedon the separable mold portions 120A-D into which they are injected.

Sacrificial material fluid heating system 202 may include any now knownor later developed sacrificial material heating unit(s) for creating asacrificial material fluid flows 286A-C at a specific temperature, e.g.,a multi-tiered heat exchanger, or a series of heating units. In thelatter example, for use with wax, heating system 202 may include aseries of Dura-Bull air pressure wax injectors, each creating fluid waxat a different temperature. In any event, sacrificial material fluidheating system 202 may be configured to heat a plurality of flows 286A-Cof the sacrificial material fluid to different temperatures. That is,each sacrificial material fluid flow 286A-C may have a differenttemperature as controlled by sacrificial material fluid heating system202. In this manner, one sacrificial material fluid input zone 290A mayreceive one of the plurality of flows of the sacrificial material fluidflows 286A at a first temperature, and another sacrificial materialfluid input zone 290B receives another sacrificial material fluid flow286B at a second, different temperature. Alternatively, one separablemold portion 120C may receive one of sacrificial material fluid flow286A at a first temperature, and another separable mold portion 120B mayreceive another sacrificial material fluid flow 286C at a second,different temperature. The temperatures can be selected to address anyof the afore-mentioned reasons for having temperature control.

In operation, as shown in the flow diagram of FIG. 22 , a method offorming casting article 102 for investment casting according toembodiments of the disclosure may include, in process P1, having aplurality of separable mold portions 120 for mold 110 for formingcasting article 102 additively manufactured, e.g., by DMLM,stereolithography, etc. As noted, plurality of mold portions 120A-D mayinclude a set of varied interchangeable versions of a selected separablemold portion, e.g., 120A, 120B, 120C or 120D (FIG. 1-2 ), or 120K, 120L,120M or 120N (FIG. 20 ). Each varied interchangeable version of theselected separable mold portion 120 may be configured to accommodate adifferent core 112 of a plurality of varied cores (FIGS. 9, 10 ).

As described, as shown in process P2, mold 110 may be formed about aselected core 112 of the plurality of varied cores 112 by coupling twoor more mold-selected separable mold portions 120 together. Themold-selected separable mold portions, i.e., those from the set(s)selected to be used in mold 110, are selected to accommodate theselected core of the plurality of varied cores. Each separable moldportion 120 may include a mold thermal conducting conduit 164 thereinconfigured to conduct temperature controlled thermal fluid 176 (FIG. 20) therethrough to control a temperature of at least the respectiveseparable mold portion, or a zone 190 in the mold. Mold 110 formationmay include fastening the two or more mold-selected separable moldportions together using fasteners 160. Mold 110 formation may alsoinclude positioning selected core 112 in mold 110 using a corepositioner receiver 144 in at least one of the plurality of separablemold portions. The positioning may include using a plurality of corepositioners 146 (FIG. 2 ) configured to position selected core 112 viacore positioner receiver 144 in the at least one of the plurality ofseparable mold portions 120. That is, selecting which from a pluralityof positioners 146 (FIG. 2 ) work for a particular core 112.Alternatively, the positioning may include using an adjustable corepositioner 146 (FIG. 19 ) in each core positioner receiver 144. Eachadjustable core positioner 146 is configured to position a number of theplurality of varied cores 112 in the mold.

Once mold 110 is formed, in process P3, casting article 102 can becasted by introducing a sacrificial material 130 fluid into the mold andabout the selected core. Process P3 may further include controlling atemperature of a plurality of sacrificial material fluid input zones190A-C (FIG. 20 ), 290A-C (FIG. 21 ) in mold 110, 210, respectively.Each zone is defined to receive the sacrificial material 130 fluid toform a sacrificial material about the core that is positioned within themold at a particular temperature. Temperature of each separable moldportion 120A-D (FIGS. 1-2 ) may also be controlled. As shown in FIG. 22, process P3 may include controlling a temperature of each of theplurality of separable mold portions and/or zones, e.g., using moldthermal fluid controller 180 alone. Alternatively, as shown in FIG. 22 ,process P3 may include heating a plurality of flows 286A-C (FIG. 21 ) ofthe sacrificial material fluid to different temperatures, e.g., usingsacrificial material fluid heating system 202, and directing one of theplurality of flows of the sacrificial material fluid, e.g., 286C, at afirst temperature to a first sacrificial material input zone 290C of themold, and directing another of the plurality of flows of sacrificialmaterial fluid, e.g., 286B, at a second, different temperature to asecond, different sacrificial material fluid input zone 290B.Alternatively, process P3 may include directing one of the plurality offlows of the sacrificial material fluid, e.g., 286B, at a firsttemperature to a first separable mold portion 120D of the mold, anddirecting another of the plurality of flows of sacrificial materialfluid, e.g., 286C, at a second, different temperature to a second,different separable mold portion 120B. Process P3 may also include usingmold thermal fluid controller 180 to control zone(s) 190A-C temperature,and sacrificial material fluid heating system 202 to control sacrificialmaterial fluid temperature in zone(s) 290A-C. Zones 190A-C as definedfor controller 180, and zones 290A-C as defined for system 202 can be,but do not need to be, identical.

Once casting article 102 is formed, mold 110 may be removed in any nowknown or later developed fashion, e.g., by unfastening mold portions120. As described, casting article 102 can be used in any now known orlater developed investment casting process.

Mold systems 100, 200 as described herein provide a number of advantagescompared to conventional systems. Mold systems 100, 200 allow for lowerpressure sacrificial material fluid injection, e.g., 34.5 kiloPascals(kPa) to 344.5 kPa (5-50 psi), compared to conventional systems, e.g.,at or above 13.8 megaPascals (MPa). Mold systems 100, 200 also allow forinjection at optimized sacrificial material fluid temperatures andviscosities since the molds have their own respective temperaturecontrol. The optimized sacrificial fluid temperatures and viscositiesand injection pressures prevent mold 110, 210 and core 112 damage due tothermal and pressure stresses. Mold systems 100, 200 also providesmodular and customizable molds to handle a variety of cores. Separablemold portions 120 can be reused, as necessary. Mold thermal fluidcontroller 180 can be used to pre-heat molds 110, 210 directly and cores112 indirectly, which aids in improving the quality of casting article102. Mold thermal fluid controller 180 also allows for precisetemperature control of defined zones and/or separable mold portions toaddress injection issues specific to that zone, mold portion and/or thecore portion located therein. Similarly, sacrificial material fluidheating system 202 allows for precise temperature control of sacrificialmaterial fluid uses for a defined zones and/or separable mold portionsto address injection issues specific to that zone, mold portion and/orthe core portion located therein. The teachings of the disclosure can beused across wide variety of mold materials, and mold manufacturingprocesses. Fleets of molds can be created to handle wide variations incores and/or different components to be built. The ability to useadditive manufacturing for both mold 110, 210 and cores 112 providessignificant time-savings and cost savings compared to conventionalcasting processes. Further, additive manufacturing allows for issuesdiscovered during formation of the casting article, e.g., core cracking,to be more quickly remedied, and also allows for the issues to beaddressed earlier in the overall process, i.e., during the castingarticle formation rather than during the investment casting process.

The foregoing drawings show some of the processing associated accordingto several embodiments of this disclosure. In this regard, each blockwithin a flow diagram of the drawings represents a process associatedwith embodiments of the method described. It should also be noted thatin some alternative implementations, the acts noted in the drawings orblocks may occur out of the order noted in the figure or, for example,may in fact be executed substantially concurrently or in the reverseorder, depending upon the act involved. Also, one of ordinary skill inthe art will recognize that additional blocks that describe theprocessing may be added.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. “Optional” or “optionally” means thatthe subsequently described event or circumstance may or may not occur,and that the description includes instances where the event occurs andinstances where it does not.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “approximately” and “substantially,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged, such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.“Approximately” as applied to a particular value of a range applies toboth values, and unless otherwise dependent on the precision of theinstrument measuring the value, may indicate +/−10% of the statedvalue(s).

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A method of forming a casting article forinvestment casting, the casting article including a core surrounded by asacrificial material, the method comprising: positioning the core withina mold configured to receive a plurality of flows of a sacrificialmaterial fluid, the mold including a plurality of sacrificial materialfluid input zones, wherein a space is formed between an exterior surfaceof the core and an interior surface of the mold by a core positioner,the space between the exterior surface of the core and the interiorsurface of the mold defining a shape of the component for the investmentcasting, and wherein the sacrificial material fluid comprises a wax orpolymer; controlling a temperature of the plurality of sacrificialmaterial fluid input zones in the mold configured to receive theplurality of flows of the sacrificial material fluid to form thesacrificial material about the core that is positioned within the mold;and forming the casting article by introducing the plurality of flows ofthe sacrificial material fluid into the mold and about the selectedcore, the forming including depositing the plurality of flows of thesacrificial material fluid via a plurality of sacrificial material fluidinputs into the space formed between the mold and the core to fill thespace formed between the exterior surface of the core and the interiorsurface of the mold with the sacrificial material, the sacrificialmaterial fluid when solidified forming the sacrificial material aboutthe core, wherein one sacrificial material fluid input zone receives oneof the plurality of flows of the sacrificial material fluid heated to afirst temperature via one of the plurality of sacrificial material fluidinputs and another sacrificial material fluid input zone receivesanother of the plurality of flows of the sacrificial material fluidheated to a second, different temperature via another of the pluralityof sacrificial material fluid inputs.
 2. The method of claim 1, whereincontrolling the temperature includes controlling the temperature of theflow of the sacrificial material fluid received in each sacrificialmaterial fluid input zone based on a characteristic of the core in therespective sacrificial material fluid input zone.
 3. The method of claim1, wherein the mold includes a plurality of separable mold portions, andwherein controlling the temperature includes controlling a temperatureof each of the plurality of separable mold portions.
 4. The method ofclaim 3, wherein each separable mold portion includes a mold thermalconducting conduit therein configured to conduct a temperaturecontrolled thermal fluid therethrough to control a temperature of atleast the respective separable mold portion, and wherein controlling thetemperature includes directing a plurality of temperature controlledthermal fluid flows through mold thermal conducting conduits ofdifferent separable mold portions.
 5. The method of claim 3, furthercomprising forming the mold about a selected core of a plurality ofvaried cores by coupling two or more mold-selected separable moldportions together, the mold-selected separable mold portions selected toaccommodate the selected core of the plurality of varied cores.
 6. Themethod of claim 5, wherein forming the mold includes fastening the twoor more mold-selected separable mold portions together using fasteners.7. The method of claim 3, wherein controlling the temperature of eachseparable mold portion includes controlling the temperature based on acharacteristic of the core in the respective separable mold portion. 8.The method of claim 7, wherein the characteristic of the core in therespective separable mold portion includes any of a fragility of thecore and a wettability of the core.
 9. The method of claim 3, whereineach separable mold portion includes at least one of the plurality ofsacrificial material fluid input zones.
 10. The method of claim 3,wherein a selected separable mold portion of the plurality of separablemold portions includes a set of varied interchangeable versions of theat least one selected separable mold portion, each variedinterchangeable version of the selected separable mold portionconfigured to accommodate a different core of a plurality of variedcores.
 11. The method of claim 10, wherein each varied interchangeableversion of the at least one selected separable mold portion includes atleast one of a different: mold opening shape, mold opening size, length,width, height, and coefficient of thermal expansion or material.